The '''FO-DOS Cartridge''' is a BIOS/BASIC 1.1 ROM upgrade for the CPC 464 from [[Duchet Computers]]. The cartridge contains a 32K BIOS/BASIC EPROM, two diodes, a LED, and a switch (for switching between old/new ROM).
Combining the FO-DOS cartridge with an additional [[Standard Memory Expansions|Standard Memory Expansion]] expansion and an external [[Amstrad Disk Drive|DDI-1]] disc drive would almost upgrade a CPC464 to a CPC6128. But the CPC464 would still not be able to use RAM configuratins &7FC1 or &7FC3 f. e.
Exact EPROM content is unknown. It might be an original or modified, english or french CPC6128 BIOS ROM...? (being made in 1989 it probably has the newer french rom). From cpcrulez forum: Boot messages says "...v3 (1985)... basic 1.1"